TABLE 4.
Antimicrobial agents investigated and resistance phenotype prevalence rates among 207 isolates from beef cattle
| Antimicrobial(s) | Proportion (%) of isolates (no. of isolates) showing resistance to antimicrobial(s) or carrying resistance gene among:
|
|||
|---|---|---|---|---|
| All isolates (n = 207) | Isolates from spring calves (n = 100) | Isolates from fall calves (n = 50) | Isolates from cows (n = 50) | |
| Amikacin | NIa | NI | NI | NI |
| Amoxicillin-clavulanic acid | 4.8 (10) | 6.5 (7) | 6.0 (3) | 0 |
| Ampicillin | 18.4 (38) | 32.7 (35) | 6.0 (3) | 0 |
| Cefoxitin | 4.8 (10) | 6.5 (7) | 6.0 (3) | 0 |
| Ceftiofur | 1.5 (3) | 1.9 (2) | 2.0 (1) | 0 |
| Ceftriaxone | 0 | 0 | 0 | 0 |
| Cephalothin | 4.8 (10) | 7.5 (8) | 4.0 (2) | 0 |
| Gentamicin | 1.0 (2) | 1.9 (2) | 0 | 0 |
| Kanamycin | 15.0 (31) | 28.0 (30) | 2.0 (1) | 0 |
| Streptomycin | 41.6 (86) | 67.3 (72) | 28.0 (14) | 0 |
| Chloramphenicol | 14.5 (30) | 25.3 (27) | 6.0 (3) | 0 |
| Ciprofloxacin | 0 | 0 | 0 | 0 |
| Nalidixic acid | 0 | 0 | 0 | 0 |
| Sulfamethoxazole | 55.1 (114) | 81.3 (87) | 52.0 (26) | 2.0 (1) |
| Tetracycline | 58.9 (122) | 87.0 (93) | 56.0 (28) | 2.0 (1) |
| Trimethoprim-sulfamethoxazole | 15.9 (33) | 29.0 (31) | 4.0 (2) | 0 |
| Total % (no.) of isolates positive for AMR | 64.7 (134) | 87.6 (94) | 78.0 (39) | 2.0 (1) |
a
NI, result not interpretable.